Tunable Interaction between Zn²⁺ and Superstructured Nb₁₈W₁₆O₉₃ Bimetallic Oxide for Multistep Tinted Electrochromic Device

Electrochromic devices (ECDs) present promising prospects in developing energy-saving applications, such as smart windows, antiglare mirrors, and information displays. Here, for the first time, we develop a multistep strategy to improve the electrochromic performance by fully using the adsorption/desorption, insertion/extraction, and reversible electrodeposition of Zn 2+ within the ECD based on the specific crystal superstructured Nb 18 W 16 O 93 film. The synergistic electrochemical process based on the Zn 2+ enables comprehensive enhancement of the electrochromic performance, such as large and broad optical modulation up to 87.0%, 96.2%, and 92.8% at 400, 633, and 1200 nm, respectively, remarkable cycling stability of 3500 cycles, and high coloration efficiency of 72.4 cm 2 C –1 . Furthermore, the assembled device delivers outstanding performance in wide-band and large optical modulation in response to a change in voltage. We believe that our multistep regulation in one device could provide a new strategy for developing high-performance ECDs and shed new light on exploring next-generation ECDs in the future.